Induced High-Yield Production of Zeaxanthin, Lutein, and β-Carotene

Jan 10, 2018 - Natural resources of zeaxanthin are extremely limited. A Chlorella zofingiensis mutant (CZ-bkt1), which could accumulate high amounts o...
0 downloads 0 Views 1MB Size
Subscriber access provided by CORNELL UNIVERSITY LIBRARY

Article

Induced high-yield production of zeaxanthin, lutein, and #-carotene by a mutant of Chlorella zofingiensis Weiping Huang, Yan Lin, Mingxia He, Yuhao Gong, and Junchao Huang J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.7b05400 • Publication Date (Web): 10 Jan 2018 Downloaded from http://pubs.acs.org on January 10, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Journal of Agricultural and Food Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 22

Journal of Agricultural and Food Chemistry

1

Induced high-yield production of zeaxanthin, lutein, and β-carotene by a

2

mutant of Chlorella zofingiensis

3

Weiping Huang, Yan Lin, Mingxia He, Yuhao Gong, Junchao Huang*

4 5 6 7

Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant

8

Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201

9 10

*corresponding author, E-mail address: [email protected]

11

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

12

ABSTRACT

13

Natural resources of zeaxanthin are extremely limited. A Chlorella zofingiensis mutant (CZ-

14

bkt1), which could accumulate high amounts of zeaxanthin, was generated and characterized.

15

CZ-bkt1 was achieved by treating the algal cells with a chemical mutagen followed by a

16

colour-based colony screening approach. CZ-bkt1 was found to consist of a dysfunctional

17

carotenoid ketolase, leading to the accumulation of zeaxanthin rather than its downstream

18

ketocarotenoid astaxanthin. Light irradiation, glucose, NaCl, and nitrogen deficiency all

19

induced CZ-bkt1 to accumulate zeaxanthin. CZ-bkt1 accumulated zeaxanthin up to

20

7.00±0.82 mg/g when induced by high light irradiation and nitrogen deficiency, and

21

36.79±2.23 mg/L by additional feeding with glucose. Furthermore, in addition to zeaxanthin,

22

CZ-bkt1 also accumulated high amounts of β-carotene (7.18±0.72 mg/g or 34.64±1.39 mg/L)

23

and lutein (13.81±1.23 mg/g or 33.97±2.61 mg/L). CZ-bkt1 is the sole species up to date with

24

the ability to accumulate high amounts of the three carotenoids that are essential for human

25

health.

26

27

KEYWORDS

28

Carotenoid; Chlorella zofingiensis; Zeaxanthin; Lutein; Microalgae

29

ACS Paragon Plus Environment

Page 2 of 22

Page 3 of 22

Journal of Agricultural and Food Chemistry

30

1. INTRODUCTION

31

Carotenoids are yellow to red pigments synthesized by all photosynthetic organisms. Lutein,

32

β-carotene, and zeaxanthin are three typical carotenoids with important biological functions.

33

They are essential nutrients for human health in that β-carotene serves as provitamin A, while

34

lutein and zeaxanthin are important pigments in the retina 1, 2. Vitamin A deficiency is a

35

public health problem in developing countries, which has prompted great efforts toward the

36

biofortification of plant-derived foods with provitamin A carotenoids 3, 4. High dietary intake

37

of zeaxanthin and lutein proved to decrease the risk of age-related macular degeneration, the

38

main cause of blindness of elder people 5. Zeaxanthin and lutein have been used as feed

39

additives and colorants in the food industry for animals 6, 7. Studies have also found that

40

zeaxanthin could reduce the risks of cataract, cancer and low-density lipoprotein oxidation 8, 9.

41

At least 2 mg/day of zeaxanthin was recommended by European Commission for adult health

42

10, 11

.

43

Microalgae have been exploited for producing high-value carotenoids, e.g. astaxanthin

44

from Haematococcus pluvialis 12, β-carotene from Dunaliella bardawill 13 and lutein from

45

Chlorella species 14. Compared with other carotenoids, zeaxanthin levels are extremely low,

46

e.g.,